1. Field of the Invention
The present invention generally relates to a method of determining whether a user is continuing a topic or switching to another topic within a search and, more particularly, to restricting the search to the previous results if the user is continuing a topic, and to searching an entire database if the user is switching topics.
2. Background Description
State of the art search engines have no notion of session history or dialog context. Prior art methods thus often return a great number of responses, and a user cannot easily determine if the desired answer is among them. Narrowing the search on a returned results set typically requires explicitly and manually adding to a previously defined search expression via a Boolean AND function or some other formal expression. If a user wants to initiate a new search outside a previous results set, he or she must take an explicit action. Some systems return results and place them in folders (i.e., categories), which the user can manually inspect and select such that a follow-on search is restricted to a particular folder or category. However, here too the user must manually indicate whether or not he or she is continuing a topic or switching topics. These modes of search are laborious, requiring that the user make many decisions and take many actions.
It is therefore an object of the invention to provide a method for iteratively drilling-down on a user""s textual free-form natural language query using a session history to interpret successive queries in the context of previous queries on a topic or topics.
It is another object of the invention to provide a method for recognizing from a user""s current free-form natural language query and a session history of previous queries by the user an implicit switch in topic.
According to the invention, by maintaining a session history of the user""s free-form natural language input and by automatically determining whether there is a topic or context switch, the search process is substantially simplified and is more effective; that is, more accurate answers to a user""s queries are found faster. In addition, as the present invention operates on free-form natural language input, automatically constructing the actual search expressions, the complexity of constructing successive search expressions is obviated.
If the system determines the user is, according to its session history and tests, asking successive questions within a given topic or context, the system keeps searching within a previously determined given set of previous responses on that context or topic. This effectively narrows the documents found allowing the user to quickly and accurately find just the documents of interest. If the system determines the user has implicitly changed context or topic, based on its session history and tests, it searches all the information at its disposal; i.e., all of the collections of documents.